﻿// Parts Copyright 2008 Newgrove Consultants Limited
// Modified By John Diss 
// From original work:
//
// Copyright 2006 - Ricardo Stuven (rstuven@gmail.com)
//
// This file is part of MsSqlSpatial.
// MsSqlSpatial is free software; you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation; either version 2 of the License, or
// (at your option) any later version.
// 
// MsSqlSpatial is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU Lesser General Public License for more details.

// You should have received a copy of the GNU Lesser General Public License
// along with MsSqlSpatial; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA 

using System.Data.SqlTypes;
using GeoAPI.Geometries;
using Microsoft.SqlServer.Server;
using MsSqlSpatial;

public partial class UserDefinedFunctions
{
    /// <summary>
    /// Returns a <c>Geometry</c> representing the points making up this
    /// <c>Geometry</c> that do not make up <c>other</c>. This method
    /// returns the closure of the resultant <c>Geometry</c>.
    /// </summary>
    /// <param name="other">The <c>Geometry</c> with which to compute the difference.</param>
    /// <returns>The point set difference of this <c>Geometry</c> with <c>other</c>.</returns>
    [SqlFunction(IsDeterministic = true)]
    public static SqlBytes Difference(SqlBytes ewkb1, SqlBytes ewkb2)
    {
        IGeometry geometry1 = ConvertGeometry.ToGeometry(ewkb1);
        if (geometry1 != null)
        {
            IGeometry geometry2 = ConvertGeometry.ToGeometry(ewkb2);
            if (geometry2 != null)
            {
                if (geometry1.Srid != geometry2.Srid)
                    throw new DifferentSridException(geometry1.Srid, geometry2.Srid);
                return ConvertGeometry.ToSqlBytes(geometry1.Difference(geometry2));
            }
        }
        return SqlBytes.Null;
    }
} ;